No one ever knows, not even a meteorologist, exactly when it will arrive and the quantum of rain it will bring. So, everybody, from the farmer and the fisherman to the political leader and the economist, come June, look heavenwards and wait for it to break and the sheets of rain to calm their fraught nerves. The farmer waits for the first signs of rain to sow the seeds; the fisherman to take advantage of the season’s fertile seas; the politician to gauge the mood of his people and the economist to chart the country’s commercial future. The monsoon is a great equaliser.
The monsoon essentially follows unequal heating of the Northern and Southern hemisphere due to the inclination of Earth’s rotation axis, and is accompanied by the transport of moisture from the oceans. This differential heating leads to large scale transfer of atmospheric mass from South to North in summer and vice-versa in winter. The monsoon, however, has become increasingly unpredictable in its arrival and largely erratic in distribution of rain, in the last few decades.
Here, the India Meteorological Department (IMD) plays an important part, as the whole nation hangs its immediate future on the weather forecast. IMD officials, however, insist it is not a prediction, but only a forecast and open to human folly when making a reading of scientific data available. Besides, the model adopted being statistical in nature, there is a possibility that on very rare occasions, the deviations from the forecast value could be wider than the model error.
The actual atmospheric variables which drive the monsoon are far too complex and involve not just regional atmospheric variables but global ones too. The dynamics are far from fully being understood to set up a system of physical equations and predict the monsoon even in the short range (three to five days ahead), let alone in the long range of two weeks or more.
There are intrinsic limits to such long-range ‘dynamic forecast’ because errors in the measurement of initial data as well as those inherent in the model, tend to double when predicted over four to five days. So, dynamical forecast even with the best of super computers, have a limited validity of about, at best, ten days. The raison d’etre for a statistical approach to long range forecast follows from this.
The IMD has forecast an ‘above normal’ southwest monsoon rain in 2016, which means that the country as a whole is expected to receive above its long-term average (LTA) of 88cm of rainfall. The June-September rainy season starts over Kerala coast and covers the rest of India and neighbouring countries – Bangladesh, Bhutan and Nepal, by mid-July. However, even though normal rainfall has been forecast for this year, the IMD said it would review its forecast around end-June after the rains cover half of the country.
The expectation of a good rainfall this year, is partly based on the rapid changes taking place in the Pacific Ocean, with El Nino conditions there receding faster and the chances of formation of La Nina – which usually boost monsoons in India – have further brightened since April. La Nina, the opposite of El Nino, is characterised by abnormal cooling of surface waters in the central and eastern equatorial Pacific. The wind patterns associated with the condition usually actively aid the southwest monsoon. According to a latest update from US Weather agency NOAA, there is now a 52 per cent chance of La Nina forming by July, which increases to 65 per cent by August and 71 per cent by September.
Monsoon rains are crucial for agriculture in India as only 46 per cent of its cultivable area is under irrigation. So, for the farming community, the monsoon means survival. If it fails, or if the distribution of rain is abnormal, it immediately reduces the earning capacity of rural India and food grain production of the country. Besides, it also affects the generation of hydro-electric power, puts a brake on industrial growth and pushes up prices.
The IMD’s prediction of a normal 2016 monsoon is comforting for the farming community, agriculture sector and the government. A good monsoon would definitely put agriculture on a sound footing. June rainfall decides areas under cultivation for major crops such as, rice, pulses, oilseeds, cotton, etc.
Equally important is the distribution of rainfall between June and September. A well-distributed and normal rainfall would help in bringing down food inflation, which is not showing any sign of abating. As monsoon progresses, prices of other commodities would also fall. Another advantage of a normal monsoon would be to recharge the ground-water system, which is overexploited.
Normally, in most parts of India, the monsoon accounts for 75-90 per cent of the total annual rainfall. The government must take advantage of the normal rainfall to plan for higher production of kharif crops, particularly pulses. The prices of pulses have skyrocketed in the last few years and refusing to come down. In view of the increasing demand for pulses due to rising income, and their limited availability in the global market, all efforts need to be made for increasing supply through area expansion and productivity increase.
The government should also popularise seeds of high yielding varieties of crops in different regions. The strategy should be for production of essential food commodities. These should be related to crop plans, availability of good seeds and other inputs, besides improved management practices.
(The writer is a freelance journalist)
